
public class Index {
    public static void main(String[] args) {
        String[] arg = new String[1];
        System.out.println("Hello world!");
        System.out.println("-->>>>>>>>>package02章_变量与运算符------");
        Main02.main(arg);

        System.out.println("-->>>>>>>>>package03章_流程控制语句------");
        Main03.main(arg);
    }

}